Cathodes for primary solid state lithium cells

Abstract

High energy density primary solid state cells using cathode materials of ionically and electronically conductive dischargeable compounds in combination with other non-conductive cathode active materials of higher energy density.

What is claimed: 
     
       1. A method for increasing the realizable primary energy density of a room temperature operable primary solid state electrochemical cell having a lithium anode, a solid electrolyte comprised of a lithium salt and having a room temperature ionic conductivity in excess of 1×10 -9  ohm -1  cm -1 , and a solid cathode comprised of a non-conductive high energy density cathode active material selected from the group consisting of sulfur, selenium, tellurium, bromine and iodine, said method consisting essentially of the step of adding to said cathode active material a second material which is both electronically and ionically conductive and which second material is also cathode active, said second material consisting of one or more metal chalcogenides having electronic and ionic conductivities ranging between 10 -10  and 10 2  ohm -1  cm -1 , whereby said cathode is substantially devoid of other electronic conductive materials and whereby said cathode contains less than 10% of other ionic conductive materials. 
     
     
       2. The method of claim 10 wherein said one or more metal chalcogenides is selected from the group consisting of CoTe 2 , Cr 2  S 3 , HfS 2 , HfSe 2 , HfTe 2 , IrTe 2 , MoS 2 , MoSe 2 , MoTe 2 , NbS 2 , NbSe 2 , NbTe 2 , NiTe 2 , PtS 2 , PtSe 2 , PtTe 2 , SnS 2 , SnSSe, SnSe 2 , TaS 2 , TaSe 2 , TaTe 2 , TiS 2 , TiSe 2 , TiTe 2 , VS 2 , VSe 2 , VTe 2 , WS 2 , WSe 2 , Wte 2 , ZrS 2 , ZrSe 2 , and ZrTe 2 . 
     
     
       3. The method of claim 2 wherein said metal chalcogenide is TiS 2 . 
     
     
       4. The method of claim 3 wherein said high energy density cathode active material is sulfur. 
     
     
       5. The method of claim 4 wherein said cathode consists of said cathode active materials without said other ionic conductive materials. 
     
     
       6. The method of claim 5 wherein said TiS 2  and said sulfur are admixed in a 1:1 mole ratio. 
     
     
       7. The method of claim 6 wherein said lithium salt is lithium iodide. 
     
     
       8. A cell made in accordance with the method of claim 1. 
     
     
       9. A cell made in accordance with the method of claim 2. 
     
     
       10. A cell made in accordance with the method of claim 3. 
     
     
       11. A cell made in accordance with the method of claim 4. 
     
     
       12. A cell made in accordance with the method of claim 5. 
     
     
       13. A cell made in accordance with the method of claim 6. 
     
     
       14. A cell made in accordance with the method of claim 7.